I'd say your mate maybe failed to properly prepare the site ,150 min of well consolidated hardcore but ensuring all topsoill removed first ,40mm layer of sand ,again compacted with a plate and then screeded off to a flat plane .The indian stone you refer to though has an uneven rear side and really needed to be set in a sand / cement screed .The reason behind my original post was that the nephew of one of my mates (simple sole trader) laid a large 200 slab patio (Indian stone) 14 months ago and he has been called back to relay 3 ‘loose’ slabs (3 visits, one slab per visit)…..he’s always gone back to put them right BUT at what point in time should he say enough is enough? He can’t guarantee them for life but ‘when‘ is an appropriate cut-off point?
In the group we also all had stories where work had been satisfactorily completed and agreed but the client had simply refused to pay (carpenter hung a new door and lady just said “I’m not paying”)……he had to take it on the chin as it was not worth the hassle or expense of getting legal.
i recently had a guy who said tramping 2" of sand with his feet and screeding off was sufficent
He was working direct to a client i had built an extension for so no issue with me but needless to say,6 months on a lot of the 450mm flags are now rocking/joints cracked etc .
take shortcuts ,get poor results .
On the time thing,if you do the job properly ,you won't need to worry about a guarantee period .
The problem is some people don't want the expense of digging out,hardcore,cement screed etc and then the worker gets the blame when it goes belly up down the line .
If a client doesn't want to pay to get the job done properly,let someone else do it would be my advice